Electromagnetic coupling device

Abstract

An electromagnetic coupling device includes an electromagnetic coil, a field core including a recessed portion containing the electromagnetic coil, and a terminal block inserted in a hole passing through the wall of the recessed portion. The terminal block includes a terminal portion projecting outside the field core, a pair of terminals provided at the terminal portion, and a pair of through holes passing through the terminal block via the pair of terminals. The winding start end and winding termination end of the electromagnetic coil pass through the pair of through holes, project from the pair of terminals, and are soldered to the pair of terminals together with a pair of external connection lead wires.

What is claimed is: 
     
       1. An electromagnetic coupling device comprising:
 an electromagnetic coil formed by winding a magnet wire including a winding start end and a winding termination end; 
 a pair of external connection lead wires including a first lead wire and a second lead wire; 
 a field core including a recessed portion containing the electromagnetic coil, and a hole passing through a wall of the recessed portion; and 
 a terminal block inserted in the hole and supported by the field core, 
 wherein the terminal block includes: 
 a terminal portion projecting outside the field core; 
 a pair of terminals provided at the terminal portion and including a first terminal and a second terminal; and 
 a first pair of through holes including a first through hole and a second through hole that pass through the terminal block via the first terminal and the second terminal, respectively, and make an outside of the field core and an inside of the recessed portion communicate with each other, 
 the winding start end passes through the first through hole, projects from the first terminal, and is soldered to the first terminal together with the first lead wire, and 
 the winding termination end passes through the second through hole, projects from the second terminal, and is soldered to the second terminal together with the second lead wire. 
 
     
     
       2. The device according to  claim 1 , wherein the terminal block further includes a pair of lead wire holding portions holding the pair of external connection lead wires along the pair of terminals,
 the first lead wire is guided onto the first terminal to cross the winding start end, and 
 the second lead wire is guided onto the second terminal to cross the winding termination end. 
 
     
     
       3. The device according to  claim 1 , further comprising a surge voltage absorber contained in the terminal block, and including one end connected to the first terminal and the other end connected to the second terminal. 
     
     
       4. The device according to  claim 2 , further comprising a surge voltage absorber contained in the terminal block, and including a third lead wire connected to the first terminal and a fourth lead wire connected to the second terminal,
 wherein the terminal block further includes a second pair of through holes including a third through hole and a fourth through hole that are bored at positions adjacent to the first through hole and the second through hole through the first terminal and the second terminal, respectively, and make the outside of the field core and the inside of the recessed portion communicate with each other, 
 the third lead wire of the surge voltage absorber projects from the first terminal through the third through hole, sandwiches the first lead wire together with the winding start end, and is soldered to the first terminal together with the winding start end and the first lead wire, and 
 the fourth lead wire of the surge voltage absorber projects from the second terminal through the fourth through hole, sandwiches the second lead wire together with the winding termination end, and is soldered to the second terminal together with the winding termination end and the second lead wire. 
 
     
     
       5. The device according to  claim 3 , wherein the surge voltage absorber is configured as a surface mount device including a package, and first and second soldering lands respectively provided at one end and the other end of the package, and is mounted in a state in which the first and second soldering lands are overlaid on the first and second terminals. 
     
     
       6. The device according to  claim 1 , wherein the terminal block further includes an inner tube fitted in the hole,
 the terminal portion is connected to an end of the inner tube that is positioned outside the field core, and 
 the first pair of through holes are formed in the inner tube and the terminal portion. 
 
     
     
       7. The device according to  claim 1 , wherein the terminal block further includes a support piece projecting from the terminal portion along an external surface of the field core. 
     
     
       8. The device according to  claim 6 , further comprising an insulator filled in the recessed portion in a state in which the electromagnetic coil is contained in the recessed portion,
 wherein the terminal block further includes: 
 a support piece projecting from the terminal portion along an external surface of the field core; and 
 a seal formed to surround the inner tube on surfaces of the terminal portion and the support piece that face the field core. 
 
     
     
       9. The device according to  claim 6 , wherein the terminal portion includes:
 a plate-like terminal block body connected to the end of the inner tube; and 
 an outer tube projecting from the terminal block body in an axial direction of the field core, and 
 the pair of terminals are formed on the terminal block body. 
 
     
     
       10. The device according to  claim 1 , wherein each of the pair of terminals includes:
 a plate portion extending along a flat external surface of the terminal portion; and 
 a plurality of projecting portions provided on two sides of the plate portion. 
 
     
     
       11. The device according to  claim 1 , wherein the terminal block includes:
 a tube fitted in the hole of the field core and including an outer end projecting outside the field core; and 
 a plate-like terminal block body provided inside the tube, and 
 the terminal portion is formed from the outer end of the tube and the terminal block body. 
 
     
     
       12. The device according to  claim 11 , wherein the tube further includes an inner end positioned inside the recessed portion of the field core, and
 the terminal block further includes a flange provided at the inner end and having an outer diameter larger than an opening width of the hole. 
 
     
     
       13. The device according to  claim 1 , further comprising:
 a rotating shaft; 
 a hub fixed to the rotating shaft; 
 an armature supported by the hub via a leaf spring; and 
 a rotor including a groove in which the field core is inserted, and a frictional surface facing the armature.